The company that owns and maintains the Baltimore police helicopter that crashed this week is the subject of a lawsuit charging negligence by two former city police officers whose helicopter went down during a routine flight six years ago.

The helicopter flown by Rennie and Crocker was the same make and model as the police aircraft that crashed Wednesday, killing Flight Officer Barry W. Wood, 50, and seriously injuring his partner, Officer Mark A. Keller.

There had been 10 pervious crashes nationwide involving the two-seat Schweizer 300C helicopter since 1995, and two fatalities associated with the accidents.

City Council President Lawrence A. Bell III said he is concerned that the crashes might point to possible mechanical problems.

He said he doesn't understand how a helicopter flown by a seasoned pilot such as Wood fell out of the sky.

"The officer was a 27-year veteran who had flown in Vietnam," Bell said. "It appears that it was a mechanical failure."

Bell said he was unaware of the 1992 crash involving Rennie and Crocker, but that it should have come to city officials' attention in 1995 when the city Board of Estimates extended a $2.1 million contract with Helicopter Transport Services to maintain the city's police helicopters.

"It wasn't brought up," Bell said. "It should have been, but it wasn't."

Bell said he plans to look into the contract with Helicopter Transport Services, the current lawsuit and what might have caused the crashes.

Peter T. Kirchen, an attorney representing the helicopter companies in Rennie and Crocker's lawsuit, declined to comment about specifics in the case or about this week's crash because the suit is pending in U.S. District Court and the other incident is under investigation.

Kathy Conlon, contracts manager for Schweizer, said investigators from the company were in Baltimore Thursday and yesterday looking into this week's crash but had not briefed company officials about the crash.

Conlon would not comment on the lawsuit.

That case was prompted by a crash on Oct. 18, 1992 in the middle of Clifton Avenue.

Rennie, a pilot with nearly 12,000 hours of flight experience, and Crocker had just helped officers on the ground find suspects in a stolen car when their 11-month-old helicopter went down about 9 p.m.

Both suffered broken vertebrae.

The officers allege in their lawsuit that as they moved into their routine flight after finding the suspects, the "engine suddenly and unexpectedly failed, resulting in a total loss of power and causing the helicopter to crash."

Rennie and Crocker contend that negligence by Helicopter Transport Services failed to determine "whether the engine and helicopter in fact were airworthy when they were released to service for use."

The manufacturer is accused of negligently designing and assembling the helicopter and engine. The company's manuals failed to adequately specify the proper type, grade and quality of fuel to be used.

The defendants denied the allegations and maintained that the helicopter was operating properly.

A Police Department incident report filed in the court case states that the helicopter's records show all scheduled maintenance was performed.

On two occasions, the helicopter required special service "due to roughness in operation or power reduction," according to the report.

On one of those occasion, a cylinder had to be replaced.

The report noted that the fuel system had not been properly tested.

The police investigation deemed the pilot and aerial observer mentally and physically capable of making the flight.